The long term objective of my research is to understand the developmental role of carbohydrate recognition during the multiple steps of synapse formation. Because neurons lose their specific carbohydrate markers upon deafferentation, we have developed the leech as a model system in which we can experimentally test the developmental function of carbohydrate recognition in an intact nervous system. Previously, we have demonstrated that different carbohydrate markers mediate sequential steps in axonal targeting. A mannose-specific recognition mediates the initial defasciculations and dispersal of axons across the target. In contrast, recognition via carbohydrate markers on complex/hybrid type glycoconjugates leads to the subsequent assembly of different axonal subset to their restricted target regions. Now we are characterizing these developmentally important leech oligosaccharides structurally by combining three different approaches. After isolating oligosaccharides by hydrazinolysis or enzymatic cleavage, we will generate different structural and compositional fingerprints of these oligosaccharides using a variety of complementary techniques such as NMR spectroscopy, GC-MS, FAB-MS, capillary zone electrophoresis interfaced with electrospray ionization mass spectrometry (CZE-ESIMS) and liquid chromatography-electrospray ionization mass spectrometry (LC-ESIMS).